How to be Green?

Yes, there is a question-mark there in the title of this post since, I am actually asking all of you how to be green? We can choose to not believe in all the global-warming talk since there are still a lot of people in the scientific community who can churn out esoteric numbers from equally obscure mathematical formulae to show how phenomenon like global warming are routine in the evolution of planets. And yet for those of us mortals living in the present time and witnessing fairly drastic changes in weather patterns and in melting icebergs, global warming seems to be the one event closest to D-day. We live our ordinary lives, believing that every thing we do is somehow contributing to earth's decay.
Needless to say that from from every form of medium of expression we are also being forewarned about global warming. However, somehow as I said, many questions still exist about how we can help in the cause of global warming. As winter descends upon most of the northern hemisphere, a mere walk in the park becomes an arduous task and we seek refuge in the warmth of man-made structures. It is at this time, I most see literally every facet of our life depend on something not natural. All the gas we consume in generating heat and keeping ourselves comfortable. So my question concerns what we can do at these times:
Is switching off the heat better during the daytime when there is so little need for a blowing hot air, or should we keep the heat on, and let the room's thermostat maintain a temperature of our desire?
If we do not unplug the electrical equipments but they are switched off---like an iron, a lamp, etc, is it still consuming power?

It would be nice to know the correct information on this---and so while my search continues, please let me know if you hear or know anything relevant.